Zone control with modulating boiler

A hydronic heating system for a building having a first area and a second area comprising:

• memory storing an instruction set and data related to a plurality of thermostat statuses, a plurality of duty cycles, a plurality of time periods, and a maximum duty cycle;
• and
• a processor for running the instruction set, the processor being in communication
• with the memory,
• wherein the processor is operative to:
• receive and store a plurality of thermostat statuses indicating whether a plurality of thermostats in a plurality of areas are on or off;
• calculate a plurality of duty cycles based on the plurality of thermostat statuses over the plurality of time periods;
• calculate a maximum duty cycle based on a greatest of the plurality of duty cycles;
• calculate a plurality of water supply values for each of the plurality of areas
• based on the duty cycle for each area and the maximum duty cycle;
• modulate a plurality of water supplies between a modulating boiler and each of the plurality of areas using a flow control valve for each area based on the respective water supply value, such that the water supplied to each area is a factor of the water supply value for said area;
• determine a target temperature for the modulating boiler based on the maximum duty cycle,
• wherein the target temperature is selected so that a maximum output of the modulating boiler is achieved before a maximum zone load for either of the first or second areas is equal to 100% for creating a hot bias to improve response when heat is called for.

A method for utilizing a modulating boiler to heat a building having a plurality of areas having a plurality of thermostats comprising the steps of:

• (a) putting each thermostat in each area in communication with a modulating boiler such that each thermostat can send a call for heat to the modulating boiler when a temperature in the area of said thermostat falls below a parameter;
• (b) setting a time period for an area;
• (c) determining a duty cycle for the area of step (b), wherein the duty cycle is based on-a total time the thermostat was calling for heat from the modulating boiler;
• (d) repeating steps (b)-(c) for each of the plurality of areas;
• (e) determining a maximum duty cycle based on a greatest of the duty cycles for each area;
• (f) determining a target temperature for the modulating boiler based on the maximum duty cycle;
• and
• (g) running the modulating boiler at or near the target temperature,
• wherein at least one of the thermostats is programmable for automatic evening setback and morning recovery, and further comprising the step of shortening the time periods around setback and recovery for improving performance.